There is a fossil about 10 centimetres in diameter within 10 centimetres of the perimeter of the green door to this building (it could be along the sides or bottom - look carefully). It is a marine creature with a shell. The animal with the shell could change the amount of gas in the shell thereby changing its buoyancy (whether it floated or sank), allowing it to move to shallow or deeper water.
Take care with this fossil as it is easily damaged.
EXERCISE: Which of the following fossil diagrams does it most closely resemble?
MARINE FOSSIL
There is a fossil about 10 centimetres in diameter within 10 centimetres of the perimeter of the green door to this building (it could be along the sides or bottom - look carefully). It is a marine creature with a shell. The animal with the shell could change the amount of gas in the shell thereby changing its buoyancy (whether it floated or sank), allowing it to move to shallow or deeper water.
Take care with this fossil as it is easily damaged.
EXERCISE: Which of the following fossil diagrams does it most closely resemble?A.
B.
C. 
D.